Wisconsinan and pre-Wisconsinan ice thicknesses on Ellesmere Island, Canada: inferences from ice cores

Study of two cores through an ice cap on northern Ellesmere Island suggests (1) during the Wisconsin Glaciation the ice near the crest was never more than about 200 m thicker than at present; (2) in a preceding glaciation, the ice was thicker than this, and the local ice divide near the boreholes was eliminated; (3) early in the Sangamon Interglacial, basal melting occurred in a deep bedrock valley south of the borehole site; and (4) the change in δ 18 O at the Wisconsinan–Holocene transition is 11‰, of which at least 8‰ results from climatic warming.